1. Field of the Invention
The present invention relates generally to connectors for differential transmission, and more particularly to a so-called straight-type connector for differential transmission to be mounted in a vertical position on a printed circuit board to have its connector connection opening parallel to the printed circuit board, the connector being applied to a part performing differential transmission of data.
2. Description of the Related Art
Differential transmission has been employed in many cases as a method of transmitting data between personal computers and peripheral devices. Differential transmission uses a pair of lines for each data element, and simultaneously transmits a “+” signal to be transmitted and a “−” signal equal in magnitude and opposite in direction to the “+” signal. Differential transmission has the advantage of being less susceptible to noise compared with a normal transmission method.
In order for differential transmission to work normally, the paired lines, one for transmitting the “+” signal and the other for the “−” signal, should be parallel and equal in length. Further, ground potential should be provided between the paired adjacent lines so that a shield is provided therebetween.
Japanese Laid-Open Patent Application No. 2001-043933 discloses a right angle-type jack connector for differential transmission to be mounted on a printed circuit board to have its connector connection opening perpendicular to the printed circuit board.
Connection modes have diversified so that there is a demand for a straight-type connector for differential transmission whose connector connection opening is parallel to a printed circuit board.
FIGS. 1A through 1C are diagrams for illustrating the case of simply converting a connector for differential transmission (differential transmission connector) of a right angle type into that of a straight type. In FIGS. 1A through 1C, X1–X2, Y1–Y2, and Z1–Z2 indicate the directions of length, the directions of width, and the directions of height, respectively, of the jack connector.
Referring to FIG. 1A, a right angle-type differential transmission jack connector 1 includes a pair of signal contact members 2 and 3, a ground contact member 4, and a housing 5. The signal contact members 2 and 3 include signal contact parts 2a and 3a, respectively, and signal terminal parts 2b and 3b, respectively. The ground contact member 4 includes a ground contact part 4a and a ground terminal part 4b. The housing 5 includes a connector connection opening 5a facing the Y2 direction.
By providing the signal contact parts 2a and 3a so that the signal contact parts 2a and 3a extend in the Z1 direction on the Y1 and Y2 sides, respectively, the right angle-type jack connector 1 is converted into a straight-type differential transmission jack connector 10 as shown in FIG. 1B. The jack connector 10 includes a pair of signal contact members 2A and 3A, a ground contact member 4A, and a housing 5A. The signal contact members 2A and 3A include signal contact parts 2Aa and 3Aa, respectively, and signal terminal parts 2Ab and 3Ab, respectively. The ground contact member 4A includes a ground contact part 4Aa and ground terminal parts 4Ab and 4Ac. The signal terminal part 2Ab extends from the signal contact part 2Aa in the Y1 direction. The signal terminal part 3Ab extends from the signal contact part 3Aa in the Y2 direction. That is, the signal terminal parts 2Ab and 3Ab extend in the opposite directions. The housing 5A includes a connector connection opening 5Aa facing the Z1, direction.
FIG. 1C shows the pattern of part of a printed circuit board 20 on which part the straight-type jack connector 10 is mounted. The pattern includes first signal pads 21, second signal pads 22, and ground pads 23. Paired first and second signal wiring patterns 31 and 32 run parallel to each other so as to couple “+” and “−” signals. A belt-like part 33 extends between the first and second signal pads 21 and 22.
The belt-like part 33 has a small width W1 so that it is difficult to form a large number of signal wiring patterns 31 and 32 in the part 33.